Wireless service providers continually try to create new markets and to expand existing markets for wireless services and equipment. One important way to accomplish this is to improve the performance of wireless network equipment while making the equipment cheaper and more reliable. Doing this allows wireless service providers to reduce infrastructure and operating costs while maintaining or even increasing the capacity of their wireless networks. At the same time, the service providers are attempting to improve the quality of wireless service and increase the quantity of services available to the end-user.
The mobile switching of a wireless network provides connections between a number of wireless network base stations and the public switched telephone network. Calls originated by or terminated at a cell phone or other mobile station are handled in the mobile station by a number of call processing client applications. A conventional mobile station typically contains a large switching fabric controlled by a main processing unit (MPU) that contains a large number of data processors and associated memories, often in the form of ASIC chips. Each of these MPU processors contains a call process client application for controlling the flow of control signals of a single call. Each call process client application in turn communicates with a call process server application that controls the flow of control signals for a large number of calls.
Thus, when a particular event occurs during a phone call (e.g., the call set-up, the invocation of three-way calling, call disconnection, or the like), control signals associated with the event are relayed from the mobile station to the call process client application in the mobile switching center (MSC). This call processing client application then relays the control signals to the call process server application, which actually performs the call processing service requested by the control signals.
Unfortunately, in large capacity systems, bottlenecks may develop around the call process server applications. Each call process client application must communicate with a particular piece of server hardware that is executing the call process server application. Due to the random nature of the starts, stops and other events in phone calls, in a large system, some servers may be near capacity and develop bottlenecks, while other servers still have plenty of adequate bandwidth. Moreover, a system failure in a particular piece of server hardware results in the loss of all call processes being handled by a call process server application being executed on the failed server.
When a new call begins (technical term is “originated”), there is a need to uniquely identify the call during its entire lifetime. The unique identity is referred to as the “call identity” and is a unique number. If any events occur during the lifetime of the call (such as answer trigger, various timeouts, hang-ups, and the like), the event is delivered to the call processing application that is handling the specific call. The call identity value is used to locate and forward the events to the correct call processing application. Conventional systems use a single server to be responsible for allocating a call identity value. The prior art server allocates any number when requested and marks that number as being in use. When the call ends, the call identity number is released and is marked by the server as being unallocated. That number may then be reused for another call. For higher availability, the server would have a backup so that if the server failed, the backup could take over. However, this approach suffers from being a bottle neck and having poor scalability.
Therefore, there is a need for improved wireless network equipment and services. In particular, there is a need for mobile switching centers that are highly reliable and minimally susceptible to bottleneck conditions during periods of high call traffic volume. More particularly, there is a need for an improved call identity server architecture for use in mobile switching centers and other similar switching devices.